Apparatus and method for fluidized bed treatment of materials

Abstract

Apparatus and method for treatment of a particulate material employs a conveyor belt for supporting the particulate material for transport and a source of gas for delivery through the conveyor belt to fluidize the particulate material. A gas distribution system is used for controlling the gas flow to create regions of greater and lesser fluidization. This approach avoids the use of mechanical agitation of the conveyor belt which improves efficiency and reliability. The apparatus and method find particular application in the handling of particulate foodstuffs in bulk when treatment such as freezing, heating, or blanching of individual food particles is required.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. An apparatus for treatment of a particulate material comprising:
 a supporting surface for the particulate material for transport between an entrance and an exit to the apparatus; 
 a gas source for delivery of a gas flow through the supporting surface and the particulate material; and 
 a gas distribution system to fluidize the particulate material on the supporting surface for the particulate material, the gas distribution system comprising a plurality of plates adjacent the supporting surface, wherein each one of the plurality of plates is formed with an array of openings therethrough to define a zone of dispersed gas flow and the plurality of plates are spaced apart by a gap between adjacent plates, each gap defining a zone of concentrated gas flow whereby the plates and the gaps between the plates co-operate to distribute the gas flow to create a plurality of repeating regions of lesser and greater fluidization, respectively, within the particulate material between the entrance and the exit, the gas source configured to deliver the gas flow upward through both the array of openings in each of the plurality of plates and each gap between the adjacent plates. 
 
     
     
       2. The apparatus as claimed in  claim 1  in which the supporting surface for the particulate material is adapted to transport the particulate material in a flow having a constant depth. 
     
     
       3. The apparatus as claimed in  claim 1  in which the supporting surface for the particulate material for transport comprises a perforated conveyor belt. 
     
     
       4. The apparatus as claimed in  claim 1  in which the gas source comprises at least one fan unit. 
     
     
       5. The apparatus as claimed in  claim 1  in which the gas is cooled air for freezing the particulate material. 
     
     
       6. The apparatus as claimed in  claim 1  in which the gas is steam for blanching the particulate material. 
     
     
       7. The apparatus as claimed in  claim 1  in which each opening of the array of openings is circular. 
     
     
       8. The apparatus as claimed in  claim 1  in which each opening of the array of openings is a slot. 
     
     
       9. The apparatus as claimed in  claim 1  in which the plurality of plates are triangular such that the gaps between adjacent plates extend obliquely to each other. 
     
     
       10. The apparatus as claimed in  claim 1  in which the plurality of plates are rectangular to define the gaps between adjacent plates that extend parallel to each other. 
     
     
       11. The apparatus as claimed in  claim 1  in which each one of the plurality of plates includes a flanged edge adjacent each gap to define a pair of flanged edges on opposite sides of the gap. 
     
     
       12. Apparatus as claimed in  claim 11  in which each pair of flanged edges is adapted to define a passage for controlling the concentrated gas flow.